Extraordinary precautions are being taken for the scheduled return to the United States Saturday of the first of two shipments of methyl isocyanate (MIC) from Brazil and France, both of which refused to accept their orders after a leak of the highly toxic gas killed at least 2,000 people in India.

The identical orders of 3,740 gallons of liquefied gas are being returned in 55-gallon drums to their American manufacturer, Union Carbide Corp., which operated the MIC plant in Bhopal, India where gas fumes escaped.

The first shipment of 68 drums is scheduled to arrive from Brazil at Norfolk International Terminal at 6 a.m. aboard the United States Lines' cargo ship American Rigel and is to be trucked to a Union Carbide plant in Woodbine, Ga.

The second shipment, from Fos, France, reportedly will arrive in Norfolk Jan. 8.

In Norfolk, the cargo is to be inspected by the Coast Guard and a Union Carbide team, with state and local police, firefighters and Virginia Department of Emergency and Energy Services representatives at dockside.

Law enforcement and state and local officials along the route through the Tidewater area and coastal North Carolina and South Carolina have been notified of the shipment.

Both batches of the chemical were produced at Union Carbide's plant in Institute, W.Va. A spokesman for West Virginia Gov. John D. (Jay) Rockefeller IV said yesterday that Union Carbide has assured him that the MIC would not be returned to that state.

The West Virginia facility is the only one other than the Bhopal plant where Union Carbide made MIC, but the Georgia plant routinely processes West Virginia-produced MIC for use in several pesticides and is expected to do so with the returning shipments.

A Union Carbide spokesman said other companies have produced MIC in Japan, West Germany, Israel, Taiwan and South Korea.

Union Carbide describes MIC as reactive, toxic, volatile and flammable, and it is considered extremely dangerous in any form.

Asked last night about how the liquid MIC being shipped differs from the liquid chemical that escaped as vapor from storage in Bhopal, Walter Goetz, director of corporate communications for Union Carbide, said that "we don't know what happened" in India.

"How it MIC got into a vapor form is the $64,000 question. If it gets into a vapor form, you don't want to mess with it," he said.

Goetz said, that in normal handling of the liquid form, the security laid on for transportation from Norfolk to Georgia would be unnecessary. "But this is an abnormal situation, and people are scared to death for no good reason at all," he added.

Representatives of several agencies involved in unloading the gas in Norfolk met last Friday and issued a statement saying the cargo "is identical to shipments which have been handled through this terminal for the past 10 years without incident."

The unloading, it said, "will be conducted in full compliance with all appropriate regulations . . . . Safety is assured for all involved in the operations and for our community."

Coast Guard Lt. Cmdr. Fred Brox said that, in addition to an inspection planned by his service, Union Carbide will conduct an inspection, which will include taking the step of unsealing the two shipping containers, each of which contains 34 drums.

"Normally, we look only for external damage and make sure the hasps have not been unlocked," Brox said. He said the chemical company was taking the extra step "probably for public relations purposes," to assure that there is no danger in transporting the gas.

"If there is no evidence of damage," Brox said, the shipping containers will be transferred to two tractor-trailer trucks.

Janet Clements of the Virginia Department of Emergency and Energy Services said state police will inspect the trucks for mechanical defects before and after the containers are loaded.

The agency also has notified officials along the route, expected to be Interstates 564 and 64 out of Norfolk, west on U.S. 58 to Emporia and south on I-95 to Georgia.

Capt. H.B. McKee of the North Carolina Highway Patrol said "we are making people aware" of the shipment.

He noted that "hazardous materials are shipped through the state all the time" and, except for nuclear materials, "there is no requirement that the shipper even notify us, much less be provided an escort."

The most elaborate precautions are planned in Georgia, where Gov. Joe Frank Harris has ordered state police to escort the two tractor-trailers to the plant south of Brunswick.

In addition, Leonard Ledbetter, Georgia's director of environmental protection, said an emergency-response team, trained in disaster drills, will monitor the shipment.

Ledbetter said that, in response to a telegram from Harris, the U.S. Occupational Safety and Health Administration announced yesterday that it had inspected the Woodbine facility and found that "it is a safe work place and that the downloading of MIC will in no way create . . . danger to workers in the plant or to the community."

The OSHA response, in a letter from regional director Alan McMillan, said federal inspectors have been in the Woodbine plant since Dec. 6 and will remain there while the chemical is processed into finished products.